What does it mean if a static inner class is also final?

Question

public class ClassWithInnerClass {

    int a = 10;

    public static void outer(){
        System.out.println("In method of outer class");

    }


        final static class Inner{

            int b = 20;

            public void innermethod(){
                System.out.println("In method of inner class");
                System.out.println("Inner class variable b = "+b);

            }
        }
}

In the above code, i have an outer class and then there is a static nested class with the non-access specifier 'final'.Does this make this class similar to "Constant" variables?

final for classes mean, than you cannot derive from that class. — AlexWien, Oct 01 '15 at 17:42
Possibly related: http://stackoverflow.com/questions/5181578/use-of-final-class-in-java — afsantos, Oct 01 '15 at 17:44
Also, it doesn't matter whether the class modified with `final` is nested or not. The behavior is the same. — Sotirios Delimanolis, Oct 01 '15 at 17:48

score 0 · Answer 1 · answered Oct 01 '15 at 17:42

0

No, it's not similar to constant variable. It means that you can't create a sub-class of this nested class (Inner). This is similar to using the final keyword in top level (i.e. not nested) classes.

answered Oct 01 '15 at 17:42

Eran

387,369
54
702
768

score 0 · Answer 2 · answered Oct 01 '15 at 17:47

final on classes mean that they cannot be extended. It's no different from having final on a class defined at the top level.

final on classes is not the same as final on variables. final has different meanings based on where you use it. In general it describes a sort of immutability:

On variables, it means that you cannot change its value once initialized.
On methods, it means that once defined, it cannot be overridden in a subclass.
On classes, it means that the class itself cannot be subclassed.

What does it mean if a static inner class is also final?

2 Answers2